One worker was in critical condition and 30 more were sickened and treated on the scene after a robot-related accident.

Twenty-four workers in an Amazon warehouse in New Jersey were hospitalized on Wednesday morning after a robot punctured a can of bear spray.

One worker was in critical condition, ABC News reported, and 30 more were sickened and treated on the scene. The primary cause for hospitalization was difficulty breathing, according to NBC New York. Bear spray contains concentrated capsaicin, the primary ingredient in pepper spray for humans.

Robbinsville town spokespeople initially said that a can of bear spray had fallen off of the shelf in the Amazon fulfillment center, NBC New York reported, but officials later said that the cause of the accident was a robot.

"All of the impacted employees have been or are expected to be released from hospital within the next 24 hours,” Amazon said in a statement shared with ABC News. “The safety of our employees is always our top priority and a full investigation is already underway. We’d like to thank all of the first responders who helped with today’s incident.”

As robots have become a more common sight in factories and warehouses around the world, there have been several high-profile accidents involving humans. In 2015, a German worker in a Volkswagen production plant was killed by a robot while he was inside the safety cage, according to local reports.

While it’s tempting to see such events as high-tech nightmares, they’re often labour issues. In April, the National Council for Occupational Safety and Health listed Amazon on its “dirty dozen” list of most dangerous companies to work for in the US, saying that seven workers have been killed in Amazon warehouses since 2013 due to “preventable” causes such as being hit by a truck or crushed by a forklift.